Spark-plug



C. A. WELLMAN.

SPARK PLUG.

APPLICATION FILED FEB. 4, I 9H 1,350,757. Patented Aug- 24, 1920.

means to cleaning UNITED STATES PATENT OFFICE.

CHARLES A. WELLMAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO WELLMAN-MUTER CORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SPARK-PLUG.

Specification of Letters Patent.

Patented Aug. 24, 19-20.

Application filed February 4, 1918. Serial No. 215,297.

To all whom it may concern:

Be it known that I, CHARLES A. VVELL- MAN,'a citizen of the United States, and a resident of the city of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Spark-Plugs; and I do hereby declare that the following is a full, clear,'and exact description of the same, reference being had to the accompanying drawings. and to the numerals of reference marked thereon, which form a part of this specification.

This invention has reference more particularly to a spark plug, which is provided with meansadapted to clean portions of the p ug. I

An object of my invention is to provide a spark plug with cleaning devices and having means at the exposed end of the plug movable outwardly therefrom for bringing the cleaning parts into position of operation.

Another object of the invention is to provide a spark plug with cleaning means which are normally positioned outwardly from the parts which they are adapted to clean and which are movable inwardly toward the plug to the cleaning position.

Another object of the invention is to pro vide a spark plug with cleaning means which are lockedin the inoperative position by a threaded engagement and separated from such engagement in the cleaning position.

Another object of the invention is to provide a spark plug with cleaning means which are held by spring tension in the cleaning position.

Another object of the invention is to provide a spark plug with cleaning means at one end and a member at the other end movable outwardly to adjust the cleaning position and sealing means movable to the sealing position by the reverse movement of the said member.

Another object of the invention is to .provide a rotary cleaning element for the inner end of the porcelain insulator, operable from the outer end thereo I Another ob'ject'of the invention is to provide a cleaning member for the porcelain insulator which is normally separated therefrom and capable of being drawn against the porcelain insulator so as to clean the same.

This invention also has other and further important objects which will be apparent from the disclosure in the specification and drawings.

The invention (in a preferred form) is illustrated in the drawings and hereinafter more fully described.

On the drawings:

Figure 1 is a side elevation of a spark plug constructed in accordance with my invention.

Fig. 2 is a bottom end view of Fig. 1.

Fig. 8 is a vertical longitudinal view taken on the line 33 of Fig 2, showing the parts in the normal position.

Fig. 4 is a view similar to Fig. 3, showing the parts in the cleaning position.

Fig. 5 is an enlarged view partly in section of the parts at the upper end of the spark plug for operating the cleaning means.

Fig. 6 is an enlarged sectional view of the lower end of the stem showing the cleaning means for the plug.

As shown on the drawings: 7

The reference numeral 1, indicates the shell or casing of the spark plug, which 1s threaded at its lower end as at 2, and provided with means for wrench connection at 3, whereby it may be secured in place on a cylinder. Mounted in the shell 1, is the insulator 4, of porcelain or other suitable material which is adapted to support and separate the central electrode of the spark plug from the shell 1. This insulator 1s enlarged intermediate of the ends so as to provide the shoulders 5 and 6, for securing the insulator in the shell 1, with the lower shoulder 5, bearing against an annular ledge 7, in the shell 1.

This spark plug is provided with cleaning means which makes it unnecessary to disassemble the plug, and the insulator 4, is

therefore permanently secured. in the shell 1, by having the flange 8, at the upper end of the shell 1, pressed or rolledinwardly over the upper shoulder 6, of the insulator 4, so as to hold the insulator 4, securely and permanently in the shell. A resilient gasket 9, is interposed between the shoulder 6, and flange 8, to relieve the shoulder 6, of undue strain. Cement 10, is interposed between the lower shoulder 5, of the insulator and the ledge 7, of-the shell 1, and may also be pressed between adjoining parts of the insulator and shell to prevent any leakage therebetween.

The stem '11, which forms the central electrode of the spark plug is passed longitudinally through the insulator 4, and a conductor 12, attached to the lower end of the shell 1, is bent inwardly so that the inner end thereof is positioned a short distance from the stem 11, to provide the usual spark gap. Attached to the stem 11, so as -to normally occupy a position intermediate of the end of-the conductor 12, and the insulator 4, is a cross head or scraper 13, which hasea concave face presented to the end of the insulator 4, and adapted to fit the end of the insulator 4, when drawn thereagainst, and this cross head 13, is preferably narrowed so as to have a scraping effect against the end of the insulator when rotated there;

4 against. The cross head 13, is designed to be operated from the outer end of the plug by means of the stem 11, and is fixed on the stem so as to move therewith. In the present instance the stem is shown in Fig. 6, with threads 14, which terminate at a point so that when the cross head 13, is

screwed on stem 11, to the end of the thread it is in the proper position.

To prevent the cross head 13, frdm coming loose, the

threads at 15, immediately under the cross head 13, are battered so that the cross head 13, will not unscrew therefrom. The cleaner cross head v13, is operated by pulling the stem 11, outwardly until the cross head 13, contacts with the lower end of the insulator 4, and a turning movement to the stem 11, then rotates the lower end of the insulator 4, and removes any deposit that may have accumulated on the end of the insulator. For cleaning the terminal 12, of the shell 1, simultaneously with the cleaning of the porcelain, I have provided a scraper 16,

which is normally positioned below the end of the terminal 12, and brought into position opposlte the terminal 12, when the scraper 13, is moved up against the lower end of the insulator 4. The scraper may be conveniently formed by flattening the lower end of the stem 11, which expands the stem laterally a suflicient amount so that when it is drawn upward opposite the terminal 12, the edges thereof will scrape against the end of the terminal a id cleanthe same.

At the outer end the insulator 4, has a tubular opening 17, in which is secured the sleeve 18. This sleeve is provided immediately above the insulator 4, with the grooved disk 19, to which the wire terminal is adapted to be connected for supplying current to'the spark plug, and thissleeve 18, is permanently secured in the upper end of the insulator 4, by means of cement or other suitable means. The sleeve 18, may have the annular groove 20, or be otherwise formed so that the cement will engage therein and securely hold the said sleeve in the insulator.

The stem 11, extends loosely through the insulator 4, and also through the sleeve 18, so as to be readily movable lengthwise thereof and. rotated therein and has a knob or finger grip 22, at its upper end for operating the stem and the cleaning parts. The

.stem is enlarged at 29, immediately below the finger grip '22, and has the coil spring 23, interposed between the upper face of the grooved disk 19, and the lower face of the finger grip 22, so as to exert a tension to separate said parts and'move the stem 11, outwardly, so that the parts 13 and 16, at the lower end thereof are in position for cleaning operation. The stem 11, is also en-' larged somewhat where,it projects into the upper end of the sleeve 18, and is threaded and the bore of the sleeve 18, is enlarged as at 25, so that the threaded portion 24, of the stem will slide longitudinally therein, without engagement except at 'the lower end of the opening 25; where there is a limited threaded portion 26, so disposed with reference to the threaded portion 24, of the stem 11, that when the parts 13 and 16, are in the cleaning position the threads 24, are

disengaged from the threads 26. A slight downward movement, however, of the stein 11, by means of the nut 22, brings the threads 24, into engagement with'the threads 26, and turning of the nut 22, causes the threaded engagement of these parts to force the stem 11, downwardly tothe normal position in which parts 13 and 16, are spaced from the parts which they are designed to clean, and the plug parts are held in the snugly in a tubular opening 28,- in the sleeve 18, when the parts are in the normal position for making the spark, and this plug 27, is removed from this opening when the nut 22, is unscrewed and the parts moved to the cleaning position. As afurther pre- 1 caution against leakage the enlarged por- -tion 29, of the stem 11, immediately below the finger grip 22, is tapered at the lower end so that when the parts are moved to the normal position the tapered portion 30, is drawn downwardly because of the threaded engagement of the threads 24, with the threads 26, and wedges against the upper edge of the opening 25, in the sleeve 18, thereby insuring a perfect .closure of the opening through the insulator 4 and the sleeve 18. Y

The operation is as follows:

Assuming that the parts are in the positions shown in Figs. 1, 3 and 5, and the plug attached on a cylinder and a conductor from the source of electric current connected with the grooved disk 19, a spark may be made between the terminal 12, and the stem 11, and the cleaning parts in no wise interfere with the making of the spark. If the spark plug becomes fouled and fails to make the spark it is not necessary to remove the plug from the cylinder, or the wire connection from the disk 19. The finger grip 22, is turned so that the threads 24 unscrew from the threads 26, and the cleaning parts 13 and 16, are thereby moved upwardly approximately to the cleaning position. As soon as the threads 24 and 26, disengage, the spring 23, forces the stem 11, upwardly until the cross head 13, bears against the insulator 4, and further turning of the finger grip 22, will thenrotate both the members 13 and 16, the former of which will scrape off from the lower end of the insulator 4, any matter that may have accumulated thereon, and the flattened portion 16, at the end of the stem 11, will scrape and clean the end of the electrode 12. After the cleaning operation the finger grip 22, is then depressed and turned so that the threads 24, engage the threads 26, and the stem 11, is then screwed down into position for making the spark. This.

movement inserts the plug 27, in the opening 28, to prevent leakage and as the parts reach the normal position the tapered shoulder 30, is forced against the upper edge of the opening 25 in thesleeve 18, and the opening through the insulator 4, thereby thoroughly sealed.

I am aware that various details of con struction may be Varied through a wide range without departing from the principles of this invention and I therefore do not purpose limiting the patent when granted otherwise than necessitated by the prior art.

I claimas my invention:

1. In a spark plug the combination with a shell, of a spark terminal thereon, an insulation core disposed in said shell, a second spark terminal supported by said insulation core, and aplurality of cleaning members on said second sparkterminal normally disposed above and below said first spark te r mina 2. In a spark plug a passaged insulation core, a movable electrode therein, a valve at -the outer end thereof for normally closing the core passage, a cleaning member engaged on said movable electrode to the inside of electrode above said cleaning head.

4. In a spark plug the combination with a shell having an electrode thereon, of an insulating member having a longitudinal electrode adapted to coiiperate with the electrode on the shell for making a spark, a cleaning member integrally formed on the end of the insulated electrode for cleaning the electrode on said shell, and a second cleaning member adjustably mounted on said insulated electrode for cleaning the insulating member.

5. In a spark plug a shell, a stationary spark terminal member thereon, a passaged insulator in said shell, a passaged threaded wire terminal member rigidly secured to the outer end of said insulator, a movable spark terminal member projecting through said passaged insulator and said wire terminal, an insulator cleaner engaged on said movable spark terminal member near the inner end thereof, a second cleaner member formed on the inner end of said movable spark terminal member for cleaning said stationary spark terminal, a valve on the outer end of said movable spark terminal member for normally closing the passage through said wire terminal member, and a spring on said movable spark terminal member providing a tension to move the cleaning members from normal position to cleaning position.

6. In a spark plug, the combination of a cleaning member, means for holding the cleaning member in the normal position, and a spring for providing a tension to move the cleaning member from the normal position.

7. In a spark plug, the combination of normally inoperative cleaning means adapted to be moved from the normal position to a position of operation, a spring exertlng a tension to move the cleaning parts from the normal position to the position of operation, and a threaded member acting against the tension of the spring to hold the cleaningmeans in the normal position.

8. In a spark plug, the combination of a insulating member having an opening therethrough, a cleaning member at the innerend of the insulating member, a valve at the outer end of the insulating member for closing the opening therethrough, and a threadscribed my name in the presence of two subed member adapted to simultaneously sepascribing witnesses.

rate the cleaning member from the part adapted to be cleaned thereby and move the CHARLES N'. 5 valve to close the opening through the in- Witnesses:

sulating member. CHARLES W. HILLS, J12,

In testimony whereof I have hereunto sub- F3121) E. PAESLER. 

